Spark-plug-insulating means.



W. F. JOHNSTON.

SPARK PLUG INSULATING MEANS.

APPLICATION FILED APR. 14 1915- Patented Apr. 17, 1917.

WARREN F. JOHNSTON, 0F WEST CARROLLTJN, OHIO.

SPARK-PLUG-INSULATING MEANS.

Specication of Letters Patent.

Patented Apr. 17, 1917.

Application tiled April 14, 1915. Serial No. 21,232.

To all whom it may concern.'

Be it known that I, WVARREN F. JOHNSTON, a citizen of the United States,residin at West Carrollton, in the county of Mntgomery and State ofOhio, have invented new and vuseful Improvements in Spark-Plug-Insulating Means, of which the following is a specilication.

This invention relates to new and useful improvements in sparkpluginsulating means.

The object of my invention is to provide an insulation for spark-plugs,which is cheaper, more efficient and durable than that which is nowemployed. Furthermore, as my improved insulation will readily take athread, less labor and fewer parts are required to insert and clamp thesame within the shell than would otherwise be necessary. Accordingly,the spark-plug may at all times be readily cleaned or repaired withlittle trouble and practically no attendant danger of breaking orOtherwise injuring the insulation or other parts during the insertion orremoval process.

The preferred forms of embodiment of my invention are illustrated in theaccompanying drawings, of which Figure 1 is an eleva.- tional view of aspark-plug, partly broken away, to disclose my improved insulating meansin place therein. Fig. 2 is a sectional View of the bakelite insulatingmember before being screwed into the shell and before the porcelaininsulation and nickel electrode has been secured thereto. Fig. 3 is asectional`view of the porcelain insulating member as constructed forinsertion in the bakelite and the reception of the electrode. Fig.

4 is an elevational view of the nickel eleo-A trode. And Fig. 5 is asectional view of the bakelite, porcelain and the nickel electrode 4allmolded together in one piece.

As is well known in the insulation art, bakelite is a condensationproduct which results when phenol and formaldehyde are boiled in thepresence of sodium hydroxid. In its solid form, it is infusible,insoluble and capable of being molded or shaped into various forms. Itreadily takes a thread, and while great heat tends to slightly softenit, it can not be brought into fusion.

Spark plugs as at present constructed, contain porcelain or mica asinsulating material. These substances cannot be threaded, andaccordingly must be held in place by numerous clamping nuts and otherparts which make the operation of inserting or removing the insulationand electrodes a diilieult one which frequently results in the breakingor injuring of the porcelain or mica and their connections.

It is with a view to obviating the above difliculties that I haveprovided the insulating member 5 which is constructed of bakelite orequivalent material; Referring to Figs. 1 and 2, the bakelite insulatingmember 5 is molded with a lower externally-threaded cylindrical end 6adapted to be screwed into the enlarged screw-threaded portion 4 of thespark-plug shell 1. Formed above its screwthreaded end 6 is an annularcollar or flange 7, above which is a hexagonal portion 8, said bakelitemember terminating at its upper end in a dome shaped portion 9. Passingthrough the central portion of the 'bakelite member 5 is a tubular bore10 adapted to readily receive the upper end of an electrode l1preferably constructed of nickel.

The tubular bore 10 Of the bakeiite meinber 5 terminates at its lowerend in an enlarged cylindrical mouth portion 12 adapted to receive theuppen end of a cylindrical insulating member 13 constructed of porcelainor other suitable silicate. This porcelain insulating member 13terminates at its lower end in a hollow or petticoat portion 14,

from which there extends upwardly through said member, a tubular bore 15having the same diameter as, and in a position to come flush with, thetubular bore 10 in the bakelite member 5.

Resting upon the upper surface of the shell 1, is a preferably copperasbestos dit upper end is tirmly within the socket or enlargedcylindrical mouth portion 12 in the bakelite insulating member 5. Thetubular bores and 15 will now be in alinement to receive the nickelelectrode 11, whose threaded end 17 is forced through and above them toreceive a terminal nut 18. Provided on the electrode 11, a shortdistance from its lowermost end, is an annular flange 19 whose diameteris Ylarger than that of the tubular bore and smaller than that oi thepetticoat portion 1d of the porcelain insulating member 13. Accordingly,when the terminal nut 18 is tightened, the electrode 11 will be elevatedto bring its flange portion 19 into engagement with the bottom of theporcelain member 13, to hold the upper end ot the latter firmly withinthe socket or enlarged cylinlrical mouth portion 12 of the bakelite mem-1Vlhen the insulating and other parts have been assembled within theshell 1 as above described, the lower end ot the electrode 11 willentend below said shell to a point a short distance above the bent endoli a side electrode 20 suitably secured within said shell, a sudicientgap being produced between the said electrodes to insure an ed'ectivespark.

From the foregoing it will appear how readily the bakelite and porcelaininsulating members may be inserted within the shell 1, and the smallnumber of parts required to firmly hold them in place. With less easemay they be inserted or removed by employing the one-piece constructionshown in lFig.. 5. lin this construction the porcelain insulating member13 preferably has the form' oit an inverted cone, whose upper endterminates in an annular flange portion 21 which is molded in the lowerthreaded end 6 of the bakelite member 5. 'lhe center nickel electrode 11is molded in both the bakelite and porcelain, and extends a Sudicientdistance below the latter to form with the side electrode 20 a gapsullicient to insure an` edective spark. Suitablycast into` the domeportion 9 of the bakelite member 5, is a hexagonal metallic piece 22having an upwardly projecting screw-threaded rod 23 adapted to receivethe terminal nut 18.

The upper end of the electrode 11 extends into the metallic piece 22,which is provided for the purpose of insuring a good electricalconnection between the J'Eeed wire (not shown) and the electrode.

The one-piece construction above described is readily screwed into andout of the shell 1, thus obviatin entirely the necessity of employingthe c amping means commonly used, and with no attendant injury to any elthe parts comprised within the insulating unit.

lt is apparent trom the foregoing that my improved process of unitingporcelain or linear/ee other suitable silicate, 'to bakelite, insuresinsulating means for a spark-plug whlch may be readily inserted in, andremoved.y

trom the shell of the plug. The small num- K .takes a thread, is screwedin the upper portion of the shell and united, by molding or, otherwise,to the porcelain below. lln other words, these two substances to wit,bakelite and porcelain, have singly qualities which, when combined in myconstruction, produce a spark-plu@ that is cheaper to manufacture, andmore ecient and durable when made, than the plugs which are commonlyused. l do not wish to be limited to the details of construction andarrangement herein shown and described, and any changes or modicationsmay be made therein'within the scope of the subjoined claims( Havingdescribed my invention, I claim: 1. lin a spark-plug, the combinationwith portion of said shell, and a silicate Insu- Bill lating memberadapted to be secured to the bottom portion of said bakelite member,substantially as described. l

2. lin a spark-plug, the combination with the shell thereof, "of abakelite insulating member threaded for insertion in the upper portionof said shell, a porcelain insulating member adapted to be Hrmly securedto the bottom portion of said bakelite member, and an electrode passingthrough both members, substantially as described.

3. ln a spark-plug, the combination with the shell thereof, of abakelite insulating member threaded for insertion in theupper portion ofsaid shell, said member provided with a tubular bore terminating at itslower end in an enlarged socket portion, a porcelain insulating memberwhose upper end is adapted to be inserted in said socket, and containinga tubular bore in a position to come Hush with the tubular bore in saidi bakelite member, and an electrode adapted to be passed through both ofsaid bores, substantially as described.

portion of said bakelite member, an electrode passing through both ofsaid members, and means attachable to said electrode for clamping saidmembers rmly together, substantially as described.

5. ln a spark-plug, the combination with the shell thereof, ot abakellte insulating lmember tl'ireaded for insertion in the upperportion ot said shell, said member provided with a vertical tubular boreterminating at its lower end in an enlarged socket portion, a porcelaininsulating member whose upper end is adapted to enter said socket, andconn taining a tubular bore in a position to come flush with the tubularbore in said b-alrelite member, an electrode with a threaded upper end,adapted to pass 'through both of said bores, a terminal nut for thethreaded end of said electrode above said bakelite member, and a flangeon the lower end oi said electrede, adapted to engage and force theporcelain member firmly against the bakelite member when said terminalnut is tightened, substantially as described.

6. In a spark-plug, the combination with the shell thereof, of a',balrelite insulating member threaded for insertion in the upper end ofsaid shell, said member provided with a vertical tubular boreterminating at its lower end in an enlarged socket portion, a porcelaininsulating member whose upper end is adapted to enter said socket, andContaining a vertical tubular bore et the same diameter as, and in aposition to come flush with, the tubular bore in said balrelite member,an electrode with a threaded upper end adapted to pass through both or'said bores, a terminal nut for the threaded end of said electrode, saidporcelain member terminating at its lower end in a petticoat portion,and a tlange on the lower end orn said electrode, adapted to passupwardly through said petticoat portion of said porcelain member, toengage and force the latter firmly against the bakelite member when theterminal nut is tightened, substantially as described.

In testimony whereof I have hereunto set my hand this 12th day of April,1915.

WARREN E JOHNSTON.

Witnesses: n

HOWARD S. SMITH, WALTER V. SNYDER.

